Differential feeding mechanism for sewing-machines



A. H. DE VOE.

DIFFERENTIAL FEEDING MECHANISM FOR SEWING MACHINES.

I APPLI KTION FILED APR. 5, I917- mlmoa B S V LE COPY PatentedSept. 23, 191% INVENTOR mfim ATTORNEY UNITED STATES PATENT OFFICE.

ALBERT H. DE VOE, 0F WESTFIELD, NEW JERSEY, ASSIGNOR TO THE SINGER MANUFACTURING COMPANY, A CORPORATION OF NEW JERSEY.

DIFFERENTIAL FEEDING MECHANISM FOR SEWING-MACHINES.

Specification of Letters latent.

Patented Sept. 23, 1919.

Original application filed March 21, 1916, Serial No. 85,535. Divided and this application filed April 5, 1917.

. Serial No. 159,888.

To all whom it may concern:

Be it known that I, ALBERT H. DE Von, a citizen of the United States, residi'n at lVestfield, in the county of Union and tate of New Jerse have invented certain new and useful mprovements in Differential Feeding Mechanisms for Sewing-Machmes, of which the following is a specification, reference being had therein to the accompanying drawings.

This mvention relates to differential feeding mechanism for sewing machines and more particularly to difierential feeding mechanism of the four-motion type wherein two feed-dogs are commonly given equal feed-and-return movements and differential rising-and-falling movements for urposes of fallin in or stretching fabric efore it is stitche The invention has for an object to provide a simplified and improved construction of difl'erential feeding mechanism comprising but few 0 rative parts and capable of quiet and e cientoperation at high speed.

More specifically, the invention has for an object to provide asimplified differential feeding mechanism adapted for use in a sewing machine having a cylindrical work-s11 porting arm and so constructed as to ta 6 up but little space within the work-supporting arm of such machine.

Accordin to the present improvement which, in t e present, instance, is embodied in a cylinder bed machine of the feed-oif-thearm type, two feed-dog-carrying bars or levers are pivotally connected together to partake of equal feed-and-return movements and differential, rising-and-falling movements. In the present embodiment of the invention, the lever which carries the forwardly disposed or auxiliary feed-do is fulcrumed between its ends upon a mova le pin carried by a pair of short, up-.standing links whose lower ends are supported upon a fixed pin. Booking and bodily endwise movements are imparted to this lever by a link-and-lever connection with a air of angularly spaced driving eccentrics xed to the main-shaft. As this lever serves to actuate both feed-dogs it may be termed the primary lever.

The other f eed-dog-car ing bar or lever carries the main or 'stitc -length defining I feed-dog and may be referred to as the secondary lever since it derives its rising-andthrough an intermediate element or differentiator pivoted to'the primary feed-lever and anchored to the frame by means of a link. In the resent instance, an adjustable pin carried y and shiftable lengthwise of the secondary lever enters a slot in the diflerentiator which acts to raise and lower the secondary lever relatively to the primer lever and differentiate the rising-and-fa ling movements of said levers during the feeding movement.

In the'accompanyin drawings Figure 1 is a side elevation o a feed-off-the-arm sewing machine head with the work-arm in section to show the improved feeding mechanism. Fig. Fig. 3 is a ragmentary longitudinal section through the work-arm showing a portion of the, feeding mechanism in plan and Fig. 4 is a detail perspective view of the difi'erentiator.

In the particular embodiment of the invention illustrated, the machine frame comprises a transversely extending body-portion l which is adapted to be supported in the manner disclosed in my copending application Serial No. 85,535, filed March 21,.1916, of which this application is a division. The ends of the body-portion 1 arefitted with bearings 2 and 3 for the main-shaft 4 which carries the feed actuating eccentrics 5 and 6 and is extended at one end beyond the bearin%3 to support the hand-wheel 7.

xtendin downwardly and rearwardly from the b0 y-portion 1 is a hollow L-shaped work-arm 8 comprisin a substantially vertical portion 9 and a su stantially horizontal portion 10 supporting a throat-plate 11.

Disposed directly above the free end of the clamped thereon by the screw 20. This 2 is a plan view of the same."

55 falling movements from the primarv lever thread-carrying gear 22 mounted on one end of a short shaft 23 journaled in the boss 13. A collar 24 secured to the other end of the shaft 23 by a.set screw 25 cotiperates with the bevelgear 22 to hold the shaft 23 in place. Meshing with the bevel-gear 22 is a similarv gear 26 carried by one end of the downwardly inclined shaft 27 journaled in bearings 28, 29. The lower forward end of shaft 27 projects into the hollow housing or body-portion 1 and carries a bevel-gear 30 which meshes with a driving gear 31 secured to the main-shaft 4 of the machine.

The presser-foot 32 is pivoted at 33 to a shank 34 carried by the presser-bar 35 mounted behind the needle-bar 16. The usual spring 36 and lifting lever 37 are employed to lower and raise the foot.

Coijperating with the needles 15 are two loopers 38 secured to a looper-support 39 mounted upon one end of the rocking and endwise movable loopershaft 40 extending within and lengthwise of the horizontal portion 10 of the work .arm. The specific construction of the mechanism for imparting operative movements to the looper-shaft is fully disclosed in my said copending application and need not be referred to-herein since it forms no part of the present improvement. I

In the specific embodiment of theinvention illustrated the differential feeding mechanism comprises the main actuating or primary lever 41 mounted for rocking and endwise movements. To'permit these move- .i'nents the lever is supported between itsendson a pin 42 carried by two, short, up-

standing links .43, one at eachjside'of the lever 41, as shown in Fig. 3. The links 43 are mounted on a horizontal pin 44 extending across and within the hollow workarm and supported by the side wall por- 'tions of said work-arm. The end of the lever 41 remote from the stitching point is curved upwardly and connected by a screwpin 45 to a pitman 46 whose upper end is provided with an eccentric strap 47.which embraces the operating eccentric 5 on the main-shaft. Secured to the other end of lever 41 by a screw 48 is an auxiliary feeddog 49 which in the. present instance is adapted to full in the work and is disposed under the forward portion of the operative surface of thepresser-foot. Y'Endwise movements are impartedto the 1ever,41-,by means of a link;50 secured thereto bya-screw-pin 51 and deriving movements from. a pin 52 adjustably mountedin aslottedarm 53--ca1fried by one end of ,a sleeve .54 surrounding and supported by the pin 55. Extending laterally from the other end of'sleeve'i54 is 65 an arm 56 connectedv to the lower end of pitan eccentric strap 58 embracing the eccentric 6 on the main-shaft.

The main feed-dog 59 is secured by a screw 60 to a secondar Y lever 61 disposed at 'one side of the primary lever .1 and including an enlarged and offset end portion 62 which is undercut so that it may straddle the lever 41 to which it is connected by a pivot pin 63. Referring to Fig. 3, the side face of the secondary lever 61 adjacent the primary lever 41 is recessed at 64 to receive a small plate 65 carrying at one end a pin 66 which projects laterally from the side face of the lever 61 adjacent the lever 41. The plate 65' is adjustable lengthwise of the lever 61 and is held in adjusted position within the recess 64 by a screw 67. Positioned between the feed levers is a difi'erentiator 68 preferably in the form of a flattened member which has a pin 69 projecting from the upper corner of one side face thereof as shown in Fig. 4. This pin 69 enters a hole in the lever 41 which serves tosupport the differentiator 68 and impart actuating movements thereto. The lower end of member 68 is anchored to the fixed pin 44 by a short link 70 which serves to control the move ment of the diiferentiator 68. It will be seen that when the primary lever 41 is moved forwa cdly the member 68 will be tilted forwardly in somewhat the same manner as the links 43.

In the present instance, a rectangular relatively to each other, when the machine is operated. However, by adjusting the pin 66 to the position shown in Figs. 1 and 3, it is evident that, with the parts in the position shown in Fig. 1, as the main-shaft is rotated in the direction of the arrow, the primary lever 41 will be moved in the direction of feed by the rising pitman 5'7 acting through the bell-crank 5 6, 53 and link 50,

and this movement of lever 41 will act through pin 69 to tilt the difl'erentiator 68 and cause the groove 71 therein to be inclined downwardly from the pin 69. Consequently the pin- 66. willqbe lowered {relatively to the pin 69' and the main on, stitch-length definingfeeddog; 59.?wi1l be. oweredrrelw tively toitheauxiliary feed dogi49ma 2pm,

As a result of this difl erential'. novement, the {stitchrlength -.o1'-;.rear.svarcl feedr dogi 59 will. drop away fromtlie. worlcand .cease its feeding actiOIiarSOoner than 1 the. luxiliary to im art motion to the differentially acting auxiliary feedogs. In other words the motions caused by eccentrics 5 and 6 are transmitted to the feed-dogs 49 and 59 through a single connecting element, to wit, the primary feed-lever 41. The said lever 41 may be considered as divided by an imaginary transverse vertical plane between the pivots 51 and 63 into two lengthwise extended portions, to one of which portions the actuating links 46 and 50 are connected and the other of which ortions supports'the main and eed-dogs. Thus the main and auxiliary feed-dogs and the feed-differentiating mechanism are disposed wholly forwardly ofthe actuating means for the feedlever 41, and the use of main and auxiliary feed bars extendin substantially the full length of the wor -arm, as heretofore, is avoided. There is thus no overlapping within the work-arm of the actuating connections for the feed-lever 41 and the feeddiflt'erentiating connections, and the space required by the feeding mechanism is accord ingly reduced to a mlnimum. While I have shown the pivot 51 as disposed comparatively near to the pivot 63, it is obvious that its position upon the bar 41 is immaterial, in the broader aspects of the invention. Adjustment of the pin 52 in the slotted arm 53 will vary the effective throw of both feeddogs without perceptibly altering their relative differential feeding action, whereas, adjustment of the pin 66, changes the effective throw of only one feed-dog, z. 6., the stitchlength feed-dog 59.

While I have shown and described in detail a specific embodiment of the invention particularly adapted for use with cylindered sewing machines it is to be understood that the embodiment illustrated is obviously susceptible of material modification both in the form and arrangement of the various parts to meet the requirements of the particular use to which the invention is to be put or, in other words, to adapt the invention to other well known types of sewing machines. The invention is not, therefore, to

be considered as limited to the exact form illustrated.

Having thus set forth the nature of the invention, what I claim herein is 1. Differential feeding mechanism for sewing machines comprisin a main-shaft, auxiliary and main feedogs, pivotally' connected primary and secondary levers supporting said feed-dogs, respectively, means connected to the main-shaft for imparting rising-and-falling and endwise feeding movements to said levers, and means whereby endwise movements of said primary lever are utilized to differentiate the rising-andfalling movements of one of said levers rela-. tively to the other.

2. Differential feeding mechanism for sewing machines comprising a rocking and endwise movable primary lever, a first feed-dog carried thereby, a secondary lever, a second feed-dog mounted thereon, and means comprising a differentiator carried by said primary ever and movable relativel to both of said levers for imparting differential movements to said secondary lever relatively to said primary lever, whereby differential feeding actions are imparted to said feeddogs.

3. Differential feeding mechanism for sewing machines comprising a supporting frame, a primary lever, a secondary lever pivoted to said primary lever, operative connections between said levers including a differentiator pivoted to said primary lever, an anchorage between said difl'erentiator and a fixed part of the machine, and an adjustable connection between said secondary lever and said differentiator for varyin the differential feeding action of the mec anism.

4. Differential feeding mechanism for sewing machines comprising a supporting frame, a primary lever, a movable fulcrum therefor, a secondary lever pivoted to said primary lever, actuating connections between saidlevers including a slotted differentiator pivoted to said primary lever, a link connecting said differentiator to a fixed part of the machine, and a pin adjustably mounted on said secondary lever and extending into said slot for varying the differential feeding action of the mechanism.

5. Differential feeding mechanism for sewing machines, comprising a rocking and endwise movable primary lever carrying a feed-dog, actuating means therefor, a secondary lever carrying another feed-dog, and

' means comprising a difi'erentiator carried by said primary lever and movable relatively to said secondary lever for imparting differential movements to said secondary lever relatively to said primary lever, whereby differential feeding actions are imparted to said feed-dogs.

6. Differential feeding mechanism for sewing machines comprising, in combination, primary and secondary feed-levers, feed-dogs carried by said levers, means for imparting fced-and-return movements to said levers, and means for imparting differential rising-and-falling movements to said levers, said last mentioned means including a differentiator pivotally connected to one feed-lever, controlling means for said differ entiator, and a pivotal connection between said differentiator and the other feed-le'ver.

7. Differential feeding 'mechanism for sewing machines comprlsing, in combination, pivotally mounted primary and secondary feed-levers, means for imparting whereby the rising-and falling movements imparted to the primary lever are transmitted to the secondary feed-lever, said means including connections-whereby the endwise feeding movements of said primary lever are caused to differentiate the rising-andfalling movements of the secondary lever relatively to the primary lever.

9. Differential feeding mechanism for sewing machines comprising, in combination, primary and secondary feed-levers disposed adjacent each other, means for imparting endwise feeding movements to sald levers, means for imparting rising-and-falling movements to said primary lever, means whereby the ri'sing-and-falling 'movements imparted to the primary lever are transmitted to the secondary feed-lever, said means including a differentiating lever pivoted to one of said feed-levers and connected to the other lever and a fulcrum connection between said differentiating lever and the frame, whereby the endwlse feeding movements of said primary lever are caused to differentiate the risingand falling move ments of the secondary lever relatively to the primary lever.

10.. In a sewing machine, in combination, a supporting frame including a hollow work-arm, stitch-forming mechanism incorporated in said frame, differential feeding mechanism disposed within said work-arm and including two work-engaging members,

means for imparting operative differential feeding movements to said members, said means including a single member disposed lengthwise of said arm through which motion is transmitted from the main shaft to both work-engaging members.

11; Differential feeding mechanism for sewing machines comprising auxiliary and stitch-length defining feed-dogs, primary 'and secondary levers supporting said feeddogs, means for imparting rising-and-falling'and substantially equal endwise feeding movements to said levers, said means including devices for converting endwise movements of one of said levers into rising-andfalling movements of the other lever relatively to said. one of said levers.

12. Differential feeding mechanism for sewing machines comprising, in combination, a lever mounted .for rocking and endwise movements, means connected to one portion along the length of said lever for imparting operative movements thereto, auxiliary and main feed-dogs connected with another distinct portion of said lever, and means whereby the operative movements of said lever are utilized to impart differential rising-and-v fallin movements to said feed-dogs.

l3; ifierential feeding mechanism for sewing machines comprising, in combination, a lever mounted for rocking and endwise movements, actuating means connected to one lengthwise extending portion of said lever for imparting said movements thereto, auxiliary and main feed-do s operatively supported by a forwardly isposed portion of said lever, and connections wholly forward of said actuating means whereby the operative movements ofsaid lever are utilized to impart differential feeding .actions to said feed-dogs.

14. Differential feeding mechanism for sewing machines comprising, in combination, a main-shaft, a primarylever having a movable fulcrum between its ends, an auxiliary feed-dog carried by said primary lever, a secondary lever connected with said primary lever and carryinga stitch-length defining feed-dog, and means carried by said primary lever between its fulcrum and the auxiliary feed-dog for imparting difi'eren-- tial movements to said secondary lever.

15. Feeding mechanism forsewing machines comprising, in combination, a pair of feed-bars, main and auxiliary feed-dogs carried .by said feed-bars, and actuating devices for imparting equal feed-and-return and differential rising-and-falling movements to said feed-bars, said actuating de vices including a diiferentiator for converting feed-and-return components of motion of one of said bars into rising-and-falling gomponents of motion of the other of said ars.

16. Feeding mechanism for sewing machines comprlsing in combination, va frame, a pair of feed-dogs, actuating mechanism incorporated in said frame for imparting substantially equal feed-and-return and dif- 'ferential rising-and-falling movements to said feed-dogs, said actuating mechanism including a pair of feed-bars and a differentiator movable relatively to said feed-bars and deriving its movement from one of said feed-bars for producing rising-and-falling movements -of the other feed-bar relatively to said first mentioned feed-bar.

17. Differential feeding mechanism for sewing machines, comprising, a frame, a primary feed-bar carrying a first feed-dog, actuating means therefor, a second feeddog, a carrier therefor mounted upon said feed-bar for rising-and-falling movements, and an anchorage between said carrier and the frame independent of the actuating means for the primary feed-bar, said anchorage including a link pivoted at one end to the frame.

18. Differential feeding mechanism for sewing machines comprising, in combination, primary and secondary feed-dogs, primary and secondary levers carrying said feed-dogs and pivotally connected together for relative rising-and-falling movements, actuating mechanism for imparting operative movements to said primary lever, and anchoring means pivotally connected to said secondary lever and independent of said actuating mechanism for connecting to the frame a point on the secondary lever spaced from the pivotal connection between said levers.

19. Differential feeding mechanism for sewing machines comprising, in combination, a main feed-bar, a forwardly disposed feed-dog carried thereby, a stitch-length-defining feed-dog, an auxiliary feed-bar carrying the latter feed-dog and pivoted to said main feed-bar for rising-and-falling movements relatively thereto, actuating means for imparting rising-and-falling and feedand-return movements to the main feed-bar, and means independent of said actuating means for differentiating the rising-and-falling movements of said feed-bars.

20. Differential feeding mechanism for sewing machines comprising, in combination, primary and secondary feed-levers, feed-dogs carried thereby, means for imparting endwise feeding movements of substantially equal amplitude to said levers, and means for imparting rising-andfalling movements to said levers includin differentiating means for transmitting t e risingand-falling movements of one lever 'to the other.

21. Differential feeding mechanism for sewing machines comprising, in combination, a frame, a feed-bar, two feed-dogs car ried thereby for difi'erential rising-and-falling movements, means for actuating said feed-bar, and a differentiator distinct from the actuating means for said feed-bar and movable relatively to said feed-dogs for differentiating their rising-and-falling movements.

22. Diflerential feeding mechanism for sewing machines comprising, a frame, a primary feed-bar carrying a first feed-do", actuating means therefor, a secondary feedbar pivotally connected to said primary feedbar and carrying a second feed-dog, and a pivoted link connection between said secondary feed-bar and the frame independent of the actuating means for the primary feedbar, said link-connection being arranged to swing in the lane of the work-engaging movement of t 10 feed-dog.

In testimony whereof, I have signed my name to this specification.

ALBERT H. DE VOE. 

